Microbiology: Module 8

Eukaryotes

A species is a group of organisms that can interbreed and produce fertile offspring.

Prokaryotes

A species is defined by genetic, biochemical, and physiological similarities because they reproduce asexually.

a strain

A genetic variant or subtype within a species

a genus

A group of closely related species.

binomial nomenclature

A two-part scientific naming system consisting of the genus and species

Genus capitalized, species lowercase, both italicized when typed (or underlined if handwritten).

How are names formatted?

Carl Linnaeus

Who developed binomial nomenclature

The appropriate international naming committee

Who makes a name "official"?

Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species

What are the taxonomic levels?

Morphology

Identification of microorganisms based on their physical characteristics (shape, size, and arrangement).

• Cocci (spherical)

• Bacilli (rod-shaped)

• Spirilla (spiral-shaped)

• Vibrio (comma-shaped)

Morphology examples

Differential Staining

Staining techniques used to distinguish microorganisms based on differences in their cell structures.

• Gram stain

• Acid-fast stain

• Endospore stain

Differential Staining examples

Biochemical Tests

Tests that identify microorganisms by their metabolic activities or enzyme production

• Catalase test

• Oxidase test

• Urease test

• Carbohydrate fermentation tests

Biochemical Tests Examples

Serology

Identification of microorganisms using antigen-antibody reactions.

• ELISA

• Agglutination test

• Western blot

Serology example

They are based on evolutionary relationships and genetic similarities between organisms

What are phylogenetic classification systems based on?

molecular chronometer

A molecule (usually DNA, RNA, or protein sequences) that changes over time at a predictable rate and is used to estimate how closely organisms are related and when they diverged

phylogenetic tree

A branching diagram that shows the evolutionary relationships and common ancestry of different organisms.

Bacteria

Bacillota

Bacilli

Lactobacillales

Lactobacillaceae

Lactobacillus

apis

Provide example for: Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species

False. They are asexual

A prokaryotic species is defined as a group of closely related organisms that breed among themselves.

Phage

In _____ typing, bacteria are classified based on the types of viruses that can infect them

True

Polymerase chain reaction can be used to identify microorganisms even when it is not possible to culture the organisms in the lab

Dichotomous keys

_____________ are used in identification through a series of questions that have two possible answers each